/*
 * Copyright 2006 - 2013
 *     Stefan Balev     <stefan.balev@graphstream-project.org>
 *     Julien Baudry    <julien.baudry@graphstream-project.org>
 *     Antoine Dutot    <antoine.dutot@graphstream-project.org>
 *     Yoann Pigné      <yoann.pigne@graphstream-project.org>
 *     Guilhelm Savin   <guilhelm.savin@graphstream-project.org>
 * 
 * This file is part of GraphStream <http://graphstream-project.org>.
 * 
 * GraphStream is a library whose purpose is to handle static or dynamic
 * graph, create them from scratch, file or any source and display them.
 * 
 * This program is free software distributed under the terms of two licenses, the
 * CeCILL-C license that fits European law, and the GNU Lesser General Public
 * License. You can  use, modify and/ or redistribute the software under the terms
 * of the CeCILL-C license as circulated by CEA, CNRS and INRIA at the following
 * URL <http://www.cecill.info> or under the terms of the GNU LGPL as published by
 * the Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * The fact that you are presently reading this means that you have had
 * knowledge of the CeCILL-C and LGPL licenses and that you accept their terms.
 */
package org.graphstream.stream;

/**
 * Source of graph events.
 * 
 * <p>
 * An source is something that produces graph events (attributes and elements),
 * but does not contain a graph instance.
 * </p>
 * 
 * @see Sink
 * @see Pipe
 */
public interface Source {
	/**
	 * Add a sink for all graph events (attributes and graph elements) coming
	 * from this source. This is similar to registering a sink for attributes an
	 * another for elements.
	 * 
	 * @param sink
	 *            The sink to register.
	 */
	void addSink(Sink sink);

	/**
	 * Remove a sink.
	 * 
	 * @param sink
	 *            The sink to remove, if it does not exist, this is ignored
	 *            silently.
	 */
	void removeSink(Sink sink);

	/**
	 * Add a sink for attribute events only. Attribute events include attribute
	 * addition change and removal.
	 * 
	 * @param sink
	 *            The sink to register.
	 */
	void addAttributeSink(AttributeSink sink);

	/**
	 * Remove an attribute sink.
	 * 
	 * @param sink
	 *            The sink to remove, if it does not exist, this is ignored
	 *            silently.
	 */
	void removeAttributeSink(AttributeSink sink);

	/**
	 * Add a sink for elements events only. Elements events include, addition
	 * and removal of nodes and edges, as well as step events.
	 * 
	 * @param sink
	 *            The sink to register.
	 */
	void addElementSink(ElementSink sink);

	/**
	 * Remove an element sink.
	 * 
	 * @param sink
	 *            The sink to remove, if it does not exist, this is ignored
	 *            silently.
	 */
	void removeElementSink(ElementSink sink);

	/**
	 * Remove all listener element sinks.
	 */
	void clearElementSinks();

	/**
	 * Remove all listener attribute sinks.
	 */
	void clearAttributeSinks();

	/**
	 * Remove all listener sinks.
	 */
	void clearSinks();
}